Simplify to lowest terms. $\dfrac{45}{25}$
Explanation: What is the greatest common factor (GCD) of 45 and 25? $45 = 3\cdot3\cdot5$ $25 = 5\cdot5$ $\mbox{GCD}(45, 25) = 5$ $\dfrac{45}{25} = \dfrac{9 \cdot 5}{ 5\cdot 5}$ $\hphantom{\dfrac{45}{25}} = \dfrac{9}{5} \cdot \dfrac{5}{5}$ $\hphantom{\dfrac{45}{25}} = \dfrac{9}{5} \cdot 1$ $\hphantom{\dfrac{45}{25}} = \dfrac{9}{5}$